Lift controlling system



Oct. 6, 1936. N 3 SMART I 2,056,626

LIFT CONTROLLING SYSTEM Filed Aug. 8, 193%" 2 Sheets-Sheet l INVENTOIR M". l. k:

INTO/WE).

Oct. 6, 1936.

N. C. SMART LIFT CONTROLLING SYSTEM Filed A g- 8, 1934 2 Sheets-Sheet 2 FLOOR F 2 lg.

I FLOOR l X I I l 1 DOM/N up 9 FLOOR I E Q 0 I I I l u I l l I //VV/V70R v. ATTORNEY Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE LIFT CONTROLLING SYSTEM London, England Application August 8, 1934, Serial No. 738,963 In Great Britain August 16, 1933 19 Claims.

This invention relates to lift controlling systems and has for an object the provision of improved means for controlling the acceleration and deceleration imparted to a lift. Another object of the invention is to provide means whereby this acceleration and deceleration are rendered substantially independent of the load carried by the lift.

In automatic or semi-automatic lift controlling systems it is known to vary the force imparted to a lift during acceleration or deceleration in accordance with the distance traveled or to be traveled, or the time for which the lift has been in motion. Also in order to obtain the quickest traverse of a lift between floors, it is known that the acceleration imparted to it must increase smoothly to a maximum from rest, then decrease to zero, and finally become negative as the lift comes once more to rest. It has previously been possible however to control the forces applied to the lift only in definite predetermined increments or decrements and the requirement as to smooth changes of acceleration has, therefore, been met hitherto only in part. Manually or automatically operated devices have provided this variation but they have been open to the objection that the same acceleration time curve is not produced in every case as the load carried by the lift usually varies within very wide limits. Again, expense and mechanical complexity have rendered fractional or gradual variation impracticable.

According to a feature of the present invention, both accelerational and decelerational forces applied to a lift may be varied gradually or in a series of small steps by an electro-magnetic stepby-step switch or switches driven at a predetermined speed so that the respective acceleration and deceleration time curves of the lift approximate closely to the best shape possible.

According to another feature of the invention means comprising a step-by-step electro-magnetic switch (or switches) positioned according to the load in the lift are provided in an automatic or semi-automatic lift-controlling system, whereby both acceleration and deceleration of the lift are rendered substantialiy independent of the load in the lift. To this end, when starting the lift from rest, a predetermined fixed force is applied to the lift and the time is measured, which the lift takes to move a fixed distance from the floor at which it is standing. This requirement is then caused to influence the lift speed controlling means in such manner as to affect all the functions of the said means to a degree dependent on the weight of the lift load.

It is found in practice that a lift controlled according to the invention, may reach any of several maxima of speed, depending on whether it has to travel between one or two or more floors without stopping; according to an additional fea- 5 ture of the invention the controlling means varying the acceleration of the lift controls also the magnitude of the decelerational force applied to the lift, and may control also the time for which the said force acts and the manner in which it varies.

It is of course possible that owing to variations in the load of the lift, or the power supply operating it, the lift may not have reached, at a particular time after commencement of acceleration 5 or deceleration, a point on its course which it should normally occupy, and according to a fur ther feature of the invention both the acceleration and deceleration controlling means are acted upon at checking points by means which may be plates or switches affixed to the side of the lift shaft to hasten or retard the travel of the lift. Alternatively, or additionally, the respective acceleration and deceleration controlling means may be acted upon by checking means controlled by the power input to the lift driving means.

In a preferred form of lift controlling system in accordance with the invention, a lift propelling motor is driven from a Ward-Leonard motor generator set, the field of the generator of which is controlled by the position of a wiper of a stepby-step switch of the type used in automatic telephone systems. The said wiper then co-operates with a contact bank having a relatively large number of contacts connected potentiometer fashion to a source of current. When the lift is to be started from rest, the switch is impulsed at a uniform rate over the potentiometer, causing an increase, which may be uniform or varying, in input to the lift propelling motor.

The position occupied by the wiper, in this preferred arrangement, is in any case dependent on the time for which it is stepped and this time will depend on the number of floors passed by the lift without stopping.

When the stop signal is given, some distance in advance of the floor at which the lift is required to come to rest, the acceleration-controlling switch, over another bank, selects a bank of a further switch which controls deceleration, the bank selected being determined by the position reached by the acceleration-controlling switch. This second bank is connected to the potentiometer previously mentioned so as to apply a deceleration-time curve to the speed at which the lift is traveling.

As the acceleration and. deceleration must not exceed a definite maximum, it is obviously necessary for the decelerational force to be applied for a longer period in the case of the lift traveling past, say, three floors, than of traveling from floor to floor, and it is arranged that the acceleration controlling switch also determines the number of checking points to be passed by the lift before coming to rest, the said points being counted by a further step-by-step switch. The checking points are plates or switches fixed to the side of the lift shaft and operated by, or operating on, the lift in its passage; they are employed in a system according to the invention to check the position of the lift against the position of the deceleration controlling switch, and for floor leveling. If a speed checking plate is not encountered at the correct part of the deceleration time curve, the rate of stepping of the deceleration controlling switch is advanced or retarded.

A similar check is applied to the acceleration switch. The output of the generator of the Ward-Leonard set to the lift-propelling motor should bear a substantially fixed relationship to the position of the acceleration controlling switch. Should this relationship not be maintained, it is so arranged that voltage operated relays in the circuit of the lift-propelling motor accelerate or retard the stepping of the acceleration controlling switch. By this means, overloading of thegenerator is avoided. If a switch of the auto-telephone type be caused to step at a fixed speed during the time taken by the lift to move a fixed distance from a floor under the influence of an input to the lift motor which input varies in a predetermined manner, then the acceleration of the lift is rendered independent of the load in thelift; the position occupied by the wiper of a bank connected as a potentiometer, at the end of this time controls the range of current supplied to the field of the g nerator of the Ward-Leonard set through the control mechanism and consequently controls the acceleration of the lift.

In order that the nature of the invention may be clearly understood, it will now be particularly described, by way of example, with reference to the accompanying drawings, of which Figure 1 is a diagram of the circuits of the relays, switches and operation connections for the lift and Figure 2 indicates the arrangement in the lift shaft of the interrupting plates for co-operation with the inductor coils.

Referring, now to Figure 1 which shows a lift controlling system, it will be seen that a motor DM drives a generator GE at a constant speed, the output of the latter being connected to the lift motor LM. This arrangement being the wellknown Ward-Leonard combination. The generatorfield GF, the current of which is controlled by means hereinafter to be described, excites the armature of the generator GE to send a variable voltage to the lift motor LM the field 28 of which is continually energized to a fixed value from a suitable source of direct current. The lift motor is coupled to a shaft on which is mounted a brake drum 29 and a winding drum 80. The latter drives a rope 22 which bears the liftcarriage 25 at one end and counterweight 83 at the other.

The lift moves in a shaft serving a number of floors, at each floor of which is a gate-operated contact 24 which is operated by the gate whilst standing at the particular floor with the gate open. The emergency-stop contact 3 in series with the gate-operated contacts 24 is placed in the'lift carriage itself and is operated when an emergency stop is required. Connection to this emergency stop contact 3, and also to other controlling items in the lift carriage is made by means of a flexible conductor 23 which hangs down the lift shaft.

The brake drum 29 is acted upon by a brake 8! which is normally pulled into contact with the drum 29 by a spring 82. The brake magnet 15, when energized, removes the brake from the drum 29, permitting the lift to be moved by its motor LM.

Assuming that it is required to cause the lift to travel a distance of several floors, the user enters the lift and closes the gate, thereby clos ing the gate operated contact 2d of that floor, thus causingoperation of the gate interlock relay J through all gate operated contacts 24 in series to earth at the emergency stop contact 3. The user then depresses, for example, up-call button I and holds it depressed, thus initiating travel in' an upward direction by operating up relay U in. series with stepping relay H and homing relay E, the circuit being from battery through coil of homing relay E, contact D2, one (upper) coil of up relay U, depressed button I, contact Ei, coil of stepping relay H to earth at contact J i (now closed). Homing relay E is slugged and is slow to operate both in picking up and in releasing so that contact El does not open for a short while. In the meantime contact U2 prevents false operation of down relay D, contact Ul locks up relay U operated to the same earth at Jl, but this time via contacts Q2, similarly contact H! holds stepping relay H operated by shortcircuiting contact El. The homing relay E new completes its operation and opens contact El. The operation of these relays completes the circuits of the generator field GF and of the controlling coils 4, 5, 6, l, 8, 9 and H3, mounted on the lift, as follows:

The field winding GF is energized over the path positive side of source 52, wiper and bank K! of load responsive switch K, resistance l 5 and 26 in parallel resistance l4, wiper and bank Si of acceleration controlling switch S, contact P5,

contact U6, generator field GF, contact U5, to

negative side of source 12. This energization on account of the resistances is relatively feeble, and causes the generator GE to supply the lift motor LM with a small current, providing a small initial driving torque to the shaft and drum 80. The lift is not at this moment moving because the brake magnet 8! still rests against the brake drum 29. The coil 8 is now supplied wit, alternating current from the circuit 85, contact U3,'contact Gl, coil 8, returning the supply 85.

The vibrator X is set into motion over the path, battery, coil of X, interrupter contact Xi, to earth at contact E3. The vibrator opens and closes contact X2, so long as this energizing circuit remains made, Contact E8 operates brake relay B, contact B! of this relay energizing brake magnet I5 and removing brake 8| from the driving shaft, allowing the lift to move slowly out of the floor at which it is standing, in a direction determined by the button I. In this case it is assumed that the direction of drive is upwards, this direction being determined by the flow of current through the generator field GF.

The vibration of contact X2 supplies impulses of earth potential via. contact H4 (now closed) and contact M2 to bank and wiper K2, the first few contacts of which are connected together, and thence to the load responsive switch magnet K, which steps these wipers KI, K2, K3 forward in synchronism with the opening and closing of contacts X2. Movement of wiper Kl over resistance II increases the current from the source [2 supplied to the potentiometer I 4, this also increasing in slight measure the energization of the generator field GF, and causing a slight increase in acceleration of the lift. It should be noted that initial acceleratory forces applied to the lift are always the same, i. e. they are independent of the load present in the lift, although the said force is always such as to be capable of moving the lift in either an upward or downward direction whether the load is a maximum or minimum. This initial movement is for the purpose of effecting control of subsequent forces applied to the lift. Obviously, if the load is excessive, then the lift moves slowly, whereas if it is light then the initial movement is faster. The load in the lift is intended to refer to the torque required of the lift motor, this torque varying with the direction of travel of the lift, whether up or down. A small torque is required to drive the lift upwards with a small load, and also to drive the lift downwards with a large load, and vice versa.

It is now necessary to refer to the portion of the drawing which comprises the electronic devices 2| and H. A transformer l6 connected to a source of alternating current 86, supplies filament current to rectifier valve I1 and also to the filaments of triodes 2|, another winding of the same transformer is connected to the anodes of the valve H, the arrangements being such as to supply high tension current to the anodes of the valves 2| via the smoothing circuit c0nsist ing of two condensers I 9 and a choke 20. The circuit to the anodes and the valves being completed through plate counting relay R. The resistance I 8 is inserted between the filaments of the valves 2| and the negative of the high tension supply, causing the filaments to be at a positive potential relative to the grids of the said triodes, the value of the resistance l8 being such as normally to cause very little current to fiow through the triodes.

The grids of the triodes are connected to a secondary of the push-pull transformer [3, the primary of which is connected through various relay contacts to lift mounted coils 5, l and 9. These coils are mounted between a further set of lift mounted coils 4, 6, 8 and Hi; all of these coils are mounted on the lift carriage although for purpose of clarity they are not shown contiguously with the carriage on the drawings. ,As will later be seen, when the lift is passing between fioors, certain of the coils 4, 6, 8 or lil are energized by alternating current from the source 85. In the present instance coil 8 is so energized over the path already described, and its field interlinks with coil 1 if not prevented by the plate shown in Figure 2, at 94. This plate, when the lift is at a floor, rests between the coils 8 and 1 so as to shield the one from the other, so that although an alternating field surrounds coils 8, l is not at the moment energized. The lift moves slowly out of the floor in the direction required until the interrupting plate 94 leaves the gap between the lift mounted coils l and 8 when the field from 8 induces a potential across coil 1, this potential being applied through contact F2 to the primary of the transformer I3. The alternating potential is thus transferred to the grids of the triodes 2| causing each one to act as an anode bend detector and increase its anode current to an appreciable amount, sufficient to operate plate counting relay R. Contact RI now operates current setting relay M from earth at contact E5. This latter relay holds itself operated via contact Ml to the same earth. Contact M2 cuts the stepping circuit of the load responsive switch K the wipers of which will then cause their movement over the banks KI, K2, K3, the bank Kl being set in a suitable position.

The operation of the plate counting relay R signifies that the lift has traveled the predetermined distance, i. e. the length of interrupting plate 94 under the influence of the predetermined drive torque derived from the generator GE, the field of which has been energized to a predetermined extent from the switch bank Kl. As the load responsive switch K has been stepping at a constant rate, the position reached by the wiper of Kl on this bank is determined by the time taken for the lift to move away from plate 94, which time is again determined by the load in the lift. Bank KI and its wiper are connected in series with the potentiometer I4, thus controlling the current through the potentiometer I 4, according to the load in the lift, i. e. the greater the load, the greater the current through the potentiometer and the greater the potential between each contact of the bank SI of the inotion controlling switch S, and banks Al, A5, and A! of the speed regulating switch A. Thus, as will be seen later, the range of the force applied to the lift carriage by the lift motor LM, depending as it does upon the energizing of generator field GF, is determined by the said wiper Kl, since this controls through the banks and wipers previously mentioned the range of the current applied to GF.

The operation of contact M2 transfers the stepping circuit of contact X2 from magnet of load responsive switch K to the first group of connections on bank S4 and from these to the wiper, and through the coil and to the battery of the magnet of the motion controlling switch S. The

latter energizes and releases at a rate corresponding to the oscillations of the bob of the relay X, and steps its wipers S! to S1 over their respective banks. The movement of wiper SI causes the potential applied to the generator field GF to increase rapidly in a series of small steps, thus increasing the potential produced by generator GE and hence the current supplied to the lift motor LM, the latter accelerating the movement of the lift carriage in the shaft. The armature of the generator GE is connected to two voltage relays V and W which operate sequentially in the order V, W as the potential of the generator GE rises. When the motion controlling switch 8 moves its wiper off the first groups of connected contacts on 84, its stepping circuit through the vibrator X2 is interrupted until the operation of voltage relay V, contact Vi of which restores the stepping circuit via the second group of con nected contacts of S4. Voltage relay W and its contact WI function in a similar mamier. The aim of these arrangements is to prevent too rapid a rise in the potential of GE and corresponding excessive output of current to the lift motor LM in the case of a heavy load being encountered. The motion controlling switch S continues stepping until its wiper S'moves off the last contact of'the 3rd group of connected contacts, when is reached, the up call button l is, however, re-

leased, thus breaking the locking circuit of stepping relay H which also releases.

The functions of certain of the banks of motion controlling switch S and speed controlling switch A must here be explained. In traveling from one floor to the next, the lift can reach only a relatively low maximum of speed and therefore needs to 'decelerate over a relatively short distance before reaching the floor at which it has to stop. If traveling between floors separated by another, a second maximum of speed may be reached and the distance during which deceleration takes place is greater. For travel between floors separated by more than one stopping place, the lift reaches yet a third maximum of speed, necessitating a still longer distance during which it is decelerated. For the purpose of controlling the lift so that it performs these functions there are provided in the lift shaft a set of interrupting plates as shown in Figure 2. In decelerating from a maximum speed in an upward direction, a row of interrupting plates such as those shown at 89, 2!, 92, 93, 94 is employed, these plates passing through gaps between lift mounted coils 9 and It, 8 and 9, and 1 and 8 respectively. Thus, in decelerating into a floor level from full speed, 5 plates pass between coils and must be counted. This number is determined by the position reached by the motion controlling switch S. Its bank S5 is connected to two selector relays F and G, the contacts of which determine which coils of the group 4--l0 are to be employed in counting plates during deceleration. In the example given, necessitating deceleration from full speed, motion controlling switch S has moved its wiper onto the last contacts of their respective banks, operating selector relays F and G from bank 85 to earth on the wipers of C5 and Ct respectively of speed checking switch C, selector relay F maintaining itself energized by closure of contact FE. Contact Gl supplies alternating current from supply 85 to the coil it, with a return to the other terminal of the supply through contact U3. Similarly coil 9 is connected to the transformer !3 by contact U4 on one side and through coil 1 on the other, so that the valves 2! are energized and plate counting relay R remains operated. When the first interrupting plate 9 is passed, induction between the soils 9 and I ceases momentarily the anode current of the valves 2! is reduced and plate counting relay R momentarily releases. Contact El now applies earth potential from contact E5 through contact H2 (stepping relay H having released) and the first contact of bank C3 to the magnet C, which in energizing breaks its own circuit through the interrupter spring contact at AC, thus stepping speed checking switch C and its wipers Ci to C6 to their second contacts. This potential also operates potentiometer relay P which its contact Pl locks to earth potential at E5. Wiper G5 new releases selector relay G. Contact GI slriort-circuits coil if! and transfers the alternating supply from 85 to coil 8. By this time, the coils have passed beyond interrupting plate 96, and the transference of the alternating supply from lift mounted coil H! to coil 8 reinduces potential in coil 9 which once more causes operation of plate counting relay R. Contact RI re-operates, speed checking switch C once more stepping via contact H3 and bank C3. The lift travels until a further interrupting plate 9| passes between the lift mounted coils 8 and 9 when induction is once more interrupted and plate counting relay R released, again stepping speed checking switch C over the path already described. In the meantime, contact X2 has been connected to the driving magnet of the speed controlling switch A over the path, wiper CI and bank second and third contacts, first contact of bank A2 and wiper, last group of connected contacts of bank S3, wiper and bank of A3, to the magnet of speed controlling switch A. This switch commences therefore to step at a rate determined by the speed of vibration of the vibrating relay X. Potential to the field coil GF ofthe generator is now reduced in a series of small steps by the wiper A! moving over its associated bank, the circuit for the generator field now being from the supply I2 through wiper and bank Kl (which throughout these operations remains at a point corresponding to the load in the lift), potentiometer l4, bank Al, bank S2, contact P5, contact. U5, generator field GF, contact U5, to negative of the supply l2. As the speed controlling switch A steps, this wiper AI moves over the potentiometer M so as to reduce potential across the coil.

Contact P2 to P5 and the associated variable resistances 2?, are found to be necessary for the purpose of changing the characteristic of the potentiometer l4. To obtain smooth acceleration, the initial steps of motion controlling switch S must make relatively small potential changes across the generator field GF, these changes increasing as the lifts speed increases. To satisfy this condition therefore, the values of the resistances connected between adjacent contacts are graded. However, smooth deceleration requires diiferent grading from that of acceleration, so the adjustable resistances 21 are connected across portions of the potentiometer as shown, their values being varied until the best effect on the lift is produced. An alternative would be to use a separate, differently graded potentiometer for deceleration, though this is apt to be more expensive and less flexible.

Switches A and C now step at intervals determined, in the case of A by the vibrator X, and that of C by the speed at which plates in the shaft are passed. These two rates of stepping should be commensurate, i. e. the stepping circuit on switch A from the vibrator contact X2 should always be complete through groups of connected contacts on A2 and Cl. Assuming, however, that switch A runs ahead, i. e. its wiper A2 reaches the second group of contacts before the interrupting second plate, e. g. 9! is counted, then the stepping circuit of speed controlling switch A is interrupted and further changes in deceleration are prevented until this second plate is counted, thus stepping speed checking switch C to the 5th contact. If, however, the interrupting plate is passed and counted before speed controlling switch A has reached a suitable position on its bank, wiper C! interrupts the stepping circuit of switch A to the vibrating contact X2, and wiper C2 connects it'to the interrupter contact AA through contact 5 of bank C2, to the first group of connected contacts on bank A2, and over the previously described path (re membering that wiper S3 is on third group) to switch A, this latter stepping at increased speed by self-interruption so that catch up with the lifts motion is effected.

Referring once more to the inductor coils 4-lil, when the speed checking switch C reaches the 5th contact, wiper C5 releases selector relay F the contact E2 of which connects one end of coil 7 to one end of the grid transformer IS, the other end of coil 1 being already connected to the opposite end of the same transformer winding. Coil 8 still remains energized over a previously described path from source 85, so that plate counting relay R remains energized until interrupting plate 92 passes between these coils and plate counting relay R is momentarily released, contact RI stepping speed checking switch C to its 7th contact. Exactly similar operations occur when interrupting plate 93 is encountered, the speed checking switch C stepping to its 9th contact.

Finally on arrival at the required floor, interrupting plate 94 enters the gap between coils T and 8 and causes release of plate counting relay R for the last time. In the meantime speed controlling switch A has been stepping via the vibrator relay contact X2 or its own interrupter contacts AA until it stands on its last level of contacts, further stepping being prevented as wiper A3 is now disconnected from the group of connected contacts on its associated bank, and therefore speed controlling switch A can no longer energize. The lift is by this time traveling very slowly, and when the final interrupting plate 94 is reached, this plate being situated at the floor at which the lift is required to stop, speed checking switch 0' steps to its 10th contact and wiper CB operates stopping relay Q, this relay locking by its contact Q! to earth at contact E4. Contact Q2 opens the circuit of up relay U and homing relay E both of which release, the latter, of course, slowly. The circuit of the generator field is opened at contacts U5 and U6. Homing relay E now opens contacts E8 which releases brake relay B, contact Bl of which deenergizes brake magnet l5 allowing brake 8! to clamp on to the associated brake drum 29 and stop the lift. Contact U3 opens the supply to the inductor coils of alternating current from the soluce B5, and contact E3 deenergizes the vibrator relay X,

the bob of which ceases to oscillate.

It is now essential to restore the switches K, S, A and C to their normal or home positions. This function is performed by various contacts of homing relay E, the typical being that of the restoration of speed checking switch C by contact E5. Earth from this contact is applied to the connected contacts on bank C4 and from thence via interrupter contacts AC to switch C, this switch stepping by self interruption until wiper C4 reaches the first contact in its bank when the homing circuit is interrupted and the switch stops in its normal position. Similarly, contact El restores motion controlling switch S, contact E2 restores load responsive switch K, and contact E6 restores speed controlling switch A.. Finally contact E4 releases stopping relay Q. Opening of the gate by the user breaks one of the contacts 24, this releases gate interlock relay J, the contact J l of which cuts the operating circuit for relays H and E and U or D, thus preventing the lift from being moved whilst the gate is open.

The operation of driving the lift in a downward direction is performed in a precisely similar manner to that already described except that the lift user depresses down call button 2 instead of up call button I, having of course, first entered the lift and shut the gate, thus operating down relay -D instead of up relay U. Contacts D5 and D6 connect current to the generator field GF through the potentiometer '14 in a reverse direction from that supplied by contacts U5 and U6. This reverses the potential of the generator and determines the direction of drive of the lift m0- tor LM. All subsequent operations take place exactly as described for an up call.

As previously stated, it is quite likely that the lift may have to travel a distance in which full speed is not attained. Under these circumstances, it is not necessary to decelerate the lift from such a distance before reaching the required floor as that necessary in the case of full speed having been reached. Motion controlling switch S will now not have reached the end of its travel before deceleration commences; for example, if the lift travels a distance of two floors, the motion controlling switch S reaches the second group of connected contacts. Thus, when deceleration is initiated by release of the up call button I or down call button 2, only selector relay F is operated so that the interrupting plate or similarly situated plates have no effect on the plate counting mechanism consisting of valves 2| and the plate counting relay R, since contact GI prevents the alternating current from being supplied by source 85 to coil Ill. The effective gap in these circumstances is therefore that between lift mounted coils 8 and 9, the interrupting plate 9i of a similarly situated one thus being the first to operate the counting mechanism. Only 4 lates nave now to be counted instead of 5 before the lift comes to rest so that the bank C6 has a connection from contact 8 to the second group of connected contacts on bank S1, this path permitting operation of stopping relay Q, i. e. the relay which initiates complete stoppage of the lift, after only 4 plates have been passed by the lift. Similarly, speed controlling switch A will not have such a large portion of the potentiometer M to run through in bringing the lift to rest, so that the number of contacts on the bank A5, which now controls deceleration through the second group of connected contacts of bank S2 and the contact P6 as less. Further, as only 4 plates are to be counted during actual movement of the lift, only three sets of connected contacts appear on bank AB which in conjunction with banks Cl and C2 act as previously described in connection with bank A2 to check the speed of switch A against the speed of the lift passing between plates.

As a last example, when the lift passes from floor to floor, even less speed is reached and therefore, a shorter period of acceleration and deceleration is required. Motion controlling switch S now ceases stepping before its wipers havemo'ved out of the first group of connected contacts on its banks, so that neither selector relay F nor G is operated and therefore only interrupting plates passing between coils 1 and 8 are counted, 1. e. only the three plates 92, 93 and or the like are effective on the valves 2| and plate counting relay R. Similarly, stopping relay Q is this time operated from the first group of connected contacts in bank S! and from earth on wiper C6 when this latter reaches contact 6 in its bank. The range of deceleration not being so great as that previously required, speed V I. previously described, 1s

controlling switch A has even less contacts to traverse this time as shown by connections of Speed reached by the lift Low Medium High Bank used A7 A5 A1 Number of plates counted 3 4 5 Plate selector relays operated- F F&G

Speed-plate count bank used- A8 A6 A2 Ooils used for deceleration 8-9 Coils used for deceleration (H 5-6 ow H H We claimi- 1. In a lift controlling system, automatic means for rendering acceleration and deceleration of the lift independent of the load, comprising a motor for the lift, a push button arranged to operate relays for starting the lift, circuits controlled by said relays for starting the motor, a wiper switch controlling current delivered to the motor, a magnet for step by step operation of said wiper switch, means for delivering impulses of current to operate said magnet and means controlled by the speed of the lift for cutting out said switch and stopping delivery of current impulses to said magnet.

2. In a lift controlling system, automatic means for rendering acceleration and deceleration of the lift independent of'the load, comprising a motor for the lift, push buttons for operating relays for starting the lift, circuits controlled by said relays for starting and controlling operation of the motor, a wiper switch cooperating with resistance coils for controlling the delivery of current to the motor, a magnet for step by step operation of the wiper switch, means for delivering current impulses for step by step operation of said switch, means operated by the lift and controlled by the load thereon for regulating the number of successive impulses of current delivered to the magnet for step by step operation of said switch.

3. In a lift controlling system as in claim 2, other wiper switches cooperating with said resistance coils for deceleration of the lift motor, magnets for operating said switches, relays controlling impulse currents for operating said magnets and lift controlled devices and circuits for controlling operation of said relays.

4. In a lift controlling system, automatic means for rendering acceleration and deceleration of the lift independent of the load, comprising a motor for the lift, push buttons controlling operation of the lift, a plurality of relays arranged to be operated by said push buttons, circuits controlled by said relays for controlling operation of the motor, a plurality of wiper switches cooperating with potentiometer. coils for controlling the delivery of current to the motor, a magnet for step by step operation of the wiper switches, means for delivering current in successive impulses to saidmagnet, the impulses being delivered at a predetermined rate, and means controlled by the distance of the lift from its starting point for cutting out operation of the magnet after the delivery thereto of a predetermined number of impulses.

5. In a lift controlling system, automatic means for rendering acceleration and deceleration of the lift independent of the load, comprising a push button arranged to operate a plurality of relays for starting the lift, a motor for operating the lift, circuits controlled by said relays'for controlling operation of wiper switches associated with resistance coils for regulating the delivery of current to the motor, a magnet for operating one of said wiper switches, means for delivering current impulses to said magnet for step by step operation of said switch to regulate delivery of current to the motor, the number of current impulses to said magnet depending on the load on the lift, a second wiper switch and potentiometer coils for controlling acceleration of the lift, a second magnet for operating the second switch, means for cutting out step by step operation of the first wiper switch after a prearranged number of impulses and starting step by step operation of the second switch and switching the impulsing current to said second magnet.

6. In a lift controlling system as in claim 5, a relay and lift controlled interacting shield plates and devices for operating said relays for deceleration of the lift and an impulse operated wiper switch controlled by said relay for utilizing said potentiometer coils in effecting deceleration of the lift.

7. In a lift controlling system, automatic means for controlling acceleration and deceleration of the lift comprising a motor for the lift, a push button for closing relay circuits for starting the lift, step-by-step wiper switches controlling resistance and potentiometer coils for regulating the speed and acceleration of the lift by controlling current to the motor, inductor coils carried by the lift and arranged to cooperate with inductor plates in the shaft for controlling deceleration and means controlled by the acceleration of the lift for determining the number of plates and inductor coils brought into operation for deceleration.

8. In a lift controlling system, automatic means for controlling acceleration and deceleration of the lift comprising a motor for the lift, potentiometer coils for controlling the speed of the motor, step-by-step wiper switches for controlling the number of potentiometer coils in circuit for regulating the speed of the motor, means for step-by-step operation of the wiper switches, a plurality of inductor coils carried by the lift, a plurality of inductor plates arranged in the lift for cooperation with the inductor coils, a relay, the operation of which is controlled by said inductor plates and coils and stepby-step wiper switches arranged to be brought into operation by said relay for controlling deceleration, said last named wiper switches operating to control the number of potentiometer coils in circuit for deceleration.

9. In a lift controlling system, automatic means for controlling acceleration and deceleration of the lift comprising a motor for the lift, resistance coils in cooperation with a wiper switch for regulating the speed of the motor,

potentiometer coils cooperating with other wiper switches for controlling acceleration and deceleration of the motor, a plurality of inductor coils carried by the lift for cooperation with a plurality of inductor plates located in spaced relation in the shaft of the lift, means controlled by the acceleration of the lift for determining the number of inductor plates and coils brought into action for deceleration and relays and wiper switches for controlling the introduction of the potentiometer coils during deceleration according to the number of inductor plates brought into action.

10. In a lift controlling system, automatic means for controlling acceleration and deceleration of the lift comprising a motor for the lift, wiper switches associated with resistance and potentiometer coils for controlling the speed and acceleration of the motor, a relay for controlling deceleration, inductor coils controlling the operation of said relay, a plurality of inductor plates in the lift shaft for each floor arranged to cooperate with the inductor coils, step-by-step wiper switches for determining the number of inductor plates to be used according to the acceleration of the lift, and other wiper switches controlled by said relay for controlling the introduction of said potentiometer coils for deceleration of the lift.

11. In a lift controlling system, automatic means for controlling acceleration and deceleration of the lift comprising a motor for the lift, step-by-step wiper switches associated with potentiometer coils for controlling acceleration and deceleration, relays for controlling deceleration, a plurality of inductor coils arranged to control the operation of one of said relays, a plu rality of inductor plates for each floor, wiper switches cooperating with other of said relays for determining the number of inductor plates to be brought into action with the inductor coils according to the number of floors traversed by the lift and step-by-step wiper switches controlled by said relay for the introduction of potentiometer coils for deceleration.

12. In a lift controlling system as in claim 11, wherein certain of said relays are arranged to be operated by said acceleration controlling wiper switches for preselecting the number of inductor plates to be utilized during deceleration, the relays operated and the number of plates utilized depending on the acceleration and the number of floors traversed.

1.3. In a lift controlling system automatic means for controlling acceleration and deceleration of the lift comprising a motor for operating the lift, circuits for controlling the delivery of current to the lift motor, tapped resistance coils for predetermining delivery of current to the lift motor according to the initial load in the lift, a step-by-step wiper switch cooperating with said tapped resistance, a magnet for stepping said switch, means for operating said magnet by current impulses, push buttons and circuits for starting and controlling operation of the lift motor, a relay controlled by the lift during its initial movement and for a prearranged distance after starting for controlling operation of said impulse means and limiting step-by-step opera-- tion of said wiper switch, the arrangement being such that said resistance is cut out so that current is thereafter delivered to the motor according to the load.

14. In a lift control system automatic means for controlling acceleration and deceleration of the lift comprising a lift motor, a potentiometer for controlling delivery of current to the motor for acceleration and deceleration, a stcp-bystep wiper switch cooperatin' with potentiometer tappings for cutting out the potentiometer resistance for acceleration of the lift according to the floors traversed, a magnet and current impulse means for stepping said wiper switch, push button controlled circuits for maintaining current impulses for step-by-step operation of said switch, a pinrality of groups of wiper contacts connected with said potentiometer tappings for cutting in the resistance for deceleration, wiper switches cooperating with the wiper contacts of the respective groups, means for selecting a predetermined wiper switch and group for controlling deceleration according to the floors traversed, a magnet cooperating with said impulse means for stepping said deceleration wiper switches and means arranged to be operated by the lift during deceleration for controlling step-by-step operation of said last named stepping magnet.

15. In a lift control system as in claim 14, a plurality of auxiliary resistance coils for changing the characteristic of the potentiometer during deceleration, a relay operating contacts for rendering said auxiliary resistance coils effective and circuits controlled by the lift during deceleration for effecting and maintaining operation of said relay.

16. In a lift control system automatic means for controlling acceleration and deceleration of the lift comprising a lift motor, a potentiometer having tappings connected with a plurality of banks of wiper contacts for regulating the speed of the lift by controlling the delivery of current to the motor, a wiper switch cooperating with one of said banks of contacts for controlling acceleration of the lift according to the floors traversed, impulse means for step-by-step operation of said switch, a plurality of deceleration wiper switches cooperating with the other of said plurality of banks of contacts, auxiliary wiper switches operated in conjunction with said acceleration switch for selecting one of said deceleration switches and its associated bank of contacts for controlling deceleration according to the floors traversed, means for step-by-step operation of said deceleration switches and means operated by the lift during deceleration and according to the floors traversed for controlling the step-bystep operation of said deceleration wiper switches.

17. A lift control system as in claim 16, wherein said means operated by the lift during deceleration comprises an independently operated wiper switch controlling step-by-step operation of said deceleration wiper switch and a relay arranged to be actuated by the lift in its movement from floor to floor provides. for the step by-step operation of said independent wiper switch.

18. In a lift control system automatic means for controlling acceleration and deceleration of the lift comprising a lift motor, a potentiometer having a plurality of tappings, a bank of wiper contacts connected with said tappings and cooperating with a wiper switch, means for stepby-step operation of said wiper switch to cut out resistance for controlling acceleration of the lift, a plurality of banks of wiper contacts connected with said tappings and cooperating with a corresponding plurality of wiper switches to cut in resistance for controlling deceleration of the lift, means for step-by-step operation of said with auxiliary Wiper switches associated with said acceleration wiper switch for selecting one of said deceleration switches for controlling deceleration of the lift according to the floors traversed, circuits and control wiper switches for controlling operation of said step-hy-step means for stepping the deceleration wiperswitches, means including a relay operated by the lift during deceleration for step-loy-step operation of said control wiper switches and interlocking circuit means between said deceleration and the control wiper switches for synchronizing and maintaining operation thereof in predetermined step-by-step relation.

19. A lift control system as in claim 18 wherein said relay operated by the lift is arranged to be operated by spaced inductor plates in the shaft cooperating with inductor coils on the lift and means is provided in association with said ac celeration wiper switch and for operation therewith for predetermining the number of plates to be counted during deceleration according to the 10 floors traversed.

NORMAN CAROL SMART. 

